okay, to put it simply --- there are a lot of vitamins naturally occurring and used and useful in the body to grow and live and breath and grow and heal and 'run things' (metabolism, digestion, nervous system, heart, lungs, kidneys, etc).
so, the God-made natural vitamins discovered in the body, in plants, etc, are good (almost ALL the time, if not all the time).
man corrupts almost everything he touches. (except for God's grace protects/controls things in spite of man and demons).
some vitamins made by man are very very good.
some are just good.
some are not good, possible. (but still better than the 'safest' drug). (so it's like a matter of comparison/safety balance).
so, test everything. just like with new foods or strange foods. take if any only a little after checking it out with someone with experiential knowledge of it as well as head knowledge. step by step. test test test.
if people did this, they would discover like the whole town of marshal , texas, that the right vitamins/diet can ... well --- read it for yourself >>> it's been nationwide news for quite a while now.
http://vegnews.com/articles/page.do?pageId=5368&catId=5
and, actually, the truth about how necessary vitamins are and how they both prevent and reverse troubles in the body has been known longer that modern 'drugs' have been around. but the money is in drugs. so what'da hear about ? drugs. why ? money. what's best? God's Way.